Livestock Nutrition

Feeding Cows

Illinois

General Information

Of the factors that influence the growth and reproductive performance of beef cows, proper nutrition is probably the most critical. Because feed costs represent over half the total cost in a cow-calf production system, it is very important to keep feed costs low while meeting your animals’ nutritional needs. Vital nutrients in beef cattle diets include water, energy, protein, calcium, phosphorus, potassium, sodium, trace minerals, and vitamins.

Types of Diets

Depending on your circumstances, you may choose from a number of feeding approaches for your herd. The traditional approach is to allow the cattle unlimited access to pasture or hay. But if the forage is not sufficiently high in protein and other nutrients, the cows may be malnourished even though they have all they can eat. Poor quality forage and crop residues have a high proportion of fiber to protein which takes longer for cows to digest. Consequently, cows can eat only about one and a half times their body weight per day of low-quality forage. If the forage is of high quality, however, cows can consume about three percent of their body weight daily. Unlimited access to feed is sometimes referred to as ad lib, short for the Latin ad libitim.

It may be necessary to supplement a low- to medium-quality forage diet with high-quality hay, or with soybean meal, grain, or co-products like distillers dried grains or corn gluten feed. With supplementation, cows can actually digest more low-quality forage—up to two percent of their body weight. Grain supplementation should be no more than 0.5 percent of the cow’s body weight (BW). If the forage is of such poor quality that more supplementation is required, you should consider using byproducts.

The most economical way to feed beef cows is to graze the cows. Brassicas and small grains with cornstalks can be used to provide fall and winter grazing very economically. If the cattle need to be fed due to snow cover or other factors related to your farm, you should develop a low cost method of feeding the cows. Following is a brief discussion of the factors influencing nutrition and some example diets. If your cows are thin or heavy milking, you will need higher energy diets than the examples provided. If your cows are larger than those described in the example, they will need proportionally more feed.

Water

Water is often the forgotten nutrient. It is important to have an adequate supply of fresh, clean water available for cattle. To be sure your water is not contaminated with chemical run-off or biological organisms, you should have it tested by one of the commercial services that are widely available.

Energy and Protein

The primary nutrients of concern for beef cattle are energy (referred to as “total digestible nutrition,” or TDN) and protein (also called “crude protein,” or CP). The example diets would need to be modified to account for these factors.

Table 1 presents the composition of common feeds, including their dry matter (DM) factor, energy and protein provided, and the presence (+, ++) or absence (-) of the macro minerals calcium, phosphorus, and potassium. Actual values vary widely—it is advisable to pay for a nutrient analysis of your forage. If you buy commercial feed mixes, you can use the content analysis provided by the manufacturer. All values are expressed on a dry-matter basis to permit comparison of feeds that vary in moisture content.

Table 1. Composition of common feedstuffs
 

Table 2 shows the typical composition of some common feeds and their prices. Using the values from this table and from Tables 1 and 3, diets were calculated for a 1,200-pound dry cow (last third of gestation) and for a 1,200-pound lactating cow in average condition with average milk production. Tables 4 and 5 show the calculated amounts and costs of various diets for these scenarios.

Table 2. Typical feedstuff values

Table 3. Hay waste

Note: Table 4 shows there is a large variation in cost per day for the diets—they range from 59 cents to $2.14 per day. If the cows were fed for 120 days, the high-cost diet for the dry cow would be $186 more (per cow) than the low-cost diet. That difference could certainly “make or break” your profit situation!

Table 4. Calculated diets for a dry cow (1,200 lbs.)

Table 5. Calculated diets for a lactating cow (1,200 lbs.)

Acknowledgments

Dan B. Faulkner, Extension Specialist, Beef
University of Illinois, Urbana-Champaign, IL
 

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audio tape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.”

Livestock Nutrition

Pasture-Based Feeding Programs for Dairy Cattle

Illinois

General Information

A successful feeding system (pasture-based system, traditional component feeding system, and Total Mixed Ration or TMR) should meet the nutrient requirements of the cow, use economical feed sources available in the area, and optimize profitability and income over feed costs. When considering a management intensive grazing (MIG) system, dairy managers must consider and manage the following factors;

1. Optimize rumen fermentation
2. Manage dry matter intake
3. Feed sorting and selection
4. Effective use of fiber
5. Economics and positioning other feeds

Optimizing Rumen Fermentation

The challenge with a pasture-based feeding program is to maintain rumen pH values from 5.8 to 6.2 that will support optimal digestibility, nitrogen flow, and desirable components. If pasture quality is less than 35% neutral detergent fiber (NDF) and over 80 percent digestibility, rumen pH can drop below 5.8. If additional fermentable carbohydrates are added such as, molasses or barley, pH levels could drop below the optimal level. However, some starch and by-product grains can stimulate microbial growth and provide needed energy.

• Maintaining rumen pH from 5.8 to 6.2 will be challenge with high quality legume grass forages. Lush pasture will be low in effective fiber due to low level of NDF (neutral detergent fiber) and rapid rate of passage. New Zealand workers reported that cows consuming only clover and grass pasture (no concentrate) experienced rumen pH under 5.5 with no supplemental grain. Adding 2 to 5 pounds of long forage particles (over one inch in length) can form and maintain a rumen or hay raft in the rumen.

• Limit the amount of a concentrate mixture to 5 to 6 pounds per meal to avoid “slug feeding” of starch leading to lower rumen pH and lactic acid formation. Providing 2 to 5 pounds of long forage prior to the grain and pasture consumption can increase rumen pH.

• Balance the rate of available nitrogen (protein) and carbohydrate degradation in the rumen by feeding grain and/or corn silage before lush pasture is consumed. The challenge is pasture that is low in rumen fermentable carbohydrate while containing excessive degradable and total protein. Feeding starch or digestible NDF (by-product feed such as corn gluten feed or soy hulls) before milking allows cows to return directly to the pasture after milking.

• Provide adequate effective fiber by maintaining a minimum of 5 pounds of forage particles that are over one inch or longer in length. Feeding 1 to 2 pounds of straw (one pound of straw functions similarly to 2 to 3 pounds of long hay), 5 pounds of baled hay, or 10 pounds of silage dry matter containing 40 to 60 percent on the top two boxes of the Penn State Particle Separator unit. These adjustments should adjust fiber levels.

• Manage rumen turnover by slowing down rapidly fermentable pasture fiber by adding some long forage to the diet. Processing grains can change the rate and site of starch fermentation while by-product feeds (such as wheat midds, soy hulls, or corn gluten feed) can dilute starch levels in grain mixtures.

Managing Dry Matter Intake

Optimizing dry matter intake is another key factor in successful pasture-based feeding systems and programs. Energy is the first limit nutrient for milk yield, milk components, and reproduction in high producing cows. Dry matter intake (energy) can be limiting to 50 pounds of 4% fat corrected milk. New Zealand researchers report cows can consume about four pounds of pasture dry matter per hour of aggressive or active grazing. Six to eight hours are the normal daily grazing times. If higher levels of milk production are desired, additional dry matter will be needed. Dairy managers have three choices: additional forage (such as corn silage), more grain, and/or a partial TMR. To enhance pasture dry matter intake, pasture can be cut and allowed to partially wilt, allowing for great dry matter consumption. Grazing activity (distance walked and slope) will require more energy (can represent 4 to 5 pounds of milk energy used for walking).

Methods to achieve higher dry matter intake (if this is economical and is your goal) will require supplemental feeds that complement pasture nutrients and do not substitute for low-priced pasture nutrient sources.

• Cows under 50 pounds of 4% fat corrected milk may support this milk yield with high quality pasture only.

• Cows producing over 50 pounds of 4% fat corrected milk will require more energy, usually gained from concentrate and silage sources (energy is limiting).

• Cows producing over 70 pounds of 4% fat corrected milk will need more energy, added rumen undegraded protein (such as heat treated soy meal), and supplemental fat (energy and amino acids are limiting at this level of production).

Adding a buffer (such as sodium bicarbonate) can increase dry matter intake by stabilizing rumen pH (adding 0.3 to 0.5 pounds per cow per day to the grain mixture or partial TMR). Buffers can reduce concentrate intake at higher levels. To improve pasture intake, offering cows a fresh allocation (new paddock or moving an electric wire) every 12 to 24 hours is a recommended procedure.

One approach to estimate pasture intake is to calculate the amount of pasture dry matter based on NDF intake. Wisconsin workers report dairy cows will consume 1.2 percent of the cow’s body weight as total NDF. Using this guideline with high quality pasture (40% NDF), a 1000 pound Jersey cow could eat 12 pounds of total NDF or 30 pounds of pasture dry matter (12 pounds divided by 0.40 which is 40% NDF in pasture expressed as a decimal). As forage NDF increases (pasture quality drops), pasture dry matter also declines reduces energy intake.

Feed Sorting and Selection

Pasture provides another challenge as cows can selectively graze legumes and/or grasses available and different plant parts (leaves or stems) leading to undesirable rumen pH and fermentation characteristics. If supplemental feeds are offered, control intake to maintain uniform consumption with adequate bunk space for feed access or along a hot wire in the pasture. One example would be to offer supplemental feed (corn silage, urea, minerals, molasses, and ear corn) prior to milking with adequate bunks which allows all cows to eat similar amounts of this partial TMR (PMR) before they milk.

For dairy cows, pastures should be clipped after each rotation to control weeds and unpalatable pasture (stems and plants going to seed). Some dairy managers will follow the lactating cows with dry cows or heifers to consume the lower quality pasture dry matter.

Effective Fiber

Based on New Zealand and Ireland data, the effective pasture NDF ranges from 35 to 40 percent. Chemical NDF pasture levels can be low at 35% NDF (U.S. forages range from 40 to 55%). New Zealand worker recommend a minimum of 15 to 17% effective NDF based on pasture (38% grass NDF times 40% effective NDF). If lush pasture contains lower NDF values (new pasture, clovers, or selective grazing), rumen pH and feed digestibility can be less than optimal. If fermentable carbohydrates are fed with these pasture qualities (such as corn or barley grain), effective NDF levels need to be raised to 18 to 20% from hay, by-product feeds, and/or straw. Estimating effective NDF is difficult and labs do not routinely offer tests. The Penn State Forage Separator Box is used to estimate effective particle length for silages and Total Mixed Rations (TMR) (percent of feed particles in the top two boxes). If effective NDF is marginal, dairy managers may observe the following characteristics.

• Low milk components, especially milk fat (drop of 0.3 to 0.5 percentage points)
• Loose manure or low fecal scores (less than 3 on a 1 to 5 range)
• Lameness and abnormal hoof growth patterns
• Free choice consumption of sodium bicarbonate
• Licking or eating of dirt
• Lack of cud chewing

Economics of Pasture-Based Feeding Systems

The profitability of pasture-based intensive pasture based systems is one factor that appeals to dairy managers. Table 1 lists university field studies comparing grazing and non-grazing farms.

Table 1. Profitability of grazing expressed as dollars of net farm income ($NFI) per cow and comparative dollar advantage of the grazing herds.
 

New York workers monitored 58 grazing herds (85 cows per herd) and 105 non-grazing herds (83 cows per herds) from 1996 to 2001. The following differences were reported:

• 1,008 pounds less milk per cow for the grazing herds
• Net farm income per cow was $71 higher for the grazing herds
• Veterinary and medicine costs were $13 less per cow for the grazing herds
• Machinery costs were $62 per cow lower for the grazing herds
• Investment per cow was $937 less per cow for the grazing herd.

These studies indicate that pasture-based systems can be economically competitive, but milk production declines must be minimized, milk cow nutrient needs must be met, and managers must avoid large investments in facilities and equipment. Dairy managers also report less hoof and leg problems, lower culling rates, and extra replacement heifers that can be sold. Dairy managers have three nutrient approaches with a pasture-based systems.

• Approach 1. Supplement 2 to 4 pounds of grain (New Zealand system) or 10 percent of the total ration dry matter. Potential milk yield could be 30 to 50 pounds of milk per cow per day or 12,000 to 15,000 pounds of milk per cow annually.

• Approach 2. Supplement 2 to 5 pounds of forage dry matter (corn silage or hay) and feed one pound of grain for each 5 pounds or 30 percent of ration dry matter. Potential milk yield could be 40 to 60 pounds of milk per cow per day or 15,000 to 17,000 pounds of milk per cow annually.

• Approach 3. Supplement 50 percent of the dry matter from PMR and 50 percent of the dry matter from pasture. Potential milk yield could be 60 to 80 pounds of milk per cow per day or 17,000 to 20,000 pound of milk per cow annually.

Acknowledgments

• Mike Hutjens, Extension Dairy Specialist, Urbana, IL
• Ed Ballard, Extension Animal Systems Educator, Forages, Effingham, IL
• Dave Fischer, Extension Animal Systems Educator, Dairy, Edwardsville, IL
• University of Illinois, Urbana, IL

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audio tape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.”

Livestock Nutrition

Relative Forage Quality (RFQ)

Illinois

General Information

Relative Forage Quality (RFQ) is a new index to rank the quality of forages. Such an index is helpful in ranking forages for sale or inventorying forages to animal groups to meet certain quality needs in the ration.

This fact sheet is a follow-up to an earlier one (November 2000) titled Forage Quality.

Relative Feed Value (RFV) has been of great value for years as a quality index for ranking cool-season grasses and legumes based on combining digestibility and intake potential. These values have been calculated from acid detergent fiber (ADF) and neutral detergent fiber (NDF).

With introduction in 2001 of new approaches to determine animal requirements in the National Research Council Nutrient Requirements for Dairy Cattle, there was an opportunity to improve RFV through use of newer analyses and equations.

Thus the concept of Relative Forage Quality (RFQ) was introduced as a method to better predict animal performance from the analysis of forages.

Differences Between RFV and RFQ

RFV is based on the concept of digestible dry matter intake relative to a standard forage according to the following formula:

RFV = (DMI, as % of BW) x (DDM, as % of DM) ÷ 1.29

Where: DMI = Dry matter intake
            DDM = Digestible dry matter
            BW = Body weight
            DM = Dry matter

Dry matter intake was estimated from neutral detergent fiber and digestible dry matter estimated from acid detergent fiber. The constant, 1.29, was chosen so that RFV = 100 for full bloom alfalfa hay. The constant was the expected DDM intake, as % of BW, for full-bloom alfalfa based on animal data.

RFQ uses the same concept and format except that TDN (total digestible nutrients) is used rather than DDM. In other words, RFQ has a digestible fiber component and is calculated as follows:

RFQ = (DMI, as % of BW) x (TDN, as % of DM) ÷ 1.23

RFQ adjusts intake for digestible fiber. Research has shown that intake is affected by digestibility of the fiber.

RFQ appears to give a much better quality estimate for grasses and legume-grass mixtures.

RFQ can be used for all forages, including warm-season grasses and brassicas (turnips, kale, rape, etc.). However, RFQ should not be used for corn silage because so much of the energy differences in corn silage relate to starch availability, which is not considered in RFQ.

Relationship Between RFV and RFQ

Summary

Due to the digestible fiber component, RFQ seems to predict animal performance better than RFV. It appears that RFQ and RFV average about the same, so RFQ can be substituted for RFV in pricing, contracts, and other uses. Note: Table 4 shows there is a large variation in cost per day for the diets—they range from 59 cents to $2.14 per day. If the cows were fed for 120 days, the high-cost diet for the dry cow would be $186 more (per cow) than the low-cost diet. That difference could certainly “make or break” your profit situation!

Where to Get Help

For more information about Relative Forage Quality, contact the local office of the Natural Resources Conservation Service or University of Illinois Extension.

Acknowledgments

Information in this fact sheet was adapted from material and work by Dr. Dan Undersander, agronomist, University of Wisconsin-Madison.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audio tape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.”